Revisiting the ORCA gene cluster that regulates terpenoid indole alkaloid biosynthesis in Catharanthus roseus

Sanjay Kumar Singh, Barunava Patra, Priyanka Paul, Yongliang Liu, Sitakanta Pattanaik, Ling Yuan

Research output: Contribution to journalArticlepeer-review

44 Scopus citations

Abstract

Transcription factor (TF) gene clusters in plants, such as tomato, potato, petunia, tobacco, and almond, have been characterized for their roles in the biosynthesis of diverse array of specialized metabolites. In Catharanthus roseus, three AP2/ERF TFs, ORCA3, ORCA4, and ORCA5, have been shown to be present on the same genomic scaffold, forming a cluster that regulates the biosynthesis of pharmaceutically important terpenoid indole alkaloids (TIAs). Our analysis of the recently updated C. roseus genome sequence revealed that the ORCA cluster comprises two additional AP2/ERFs, the previously characterized ORCA2 and a newly identified member designated as ORCA6. Transcriptomic analysis revealed that the ORCAs are highly expressed in stems, followed by leaves, roots and flowers. Expression of ORCAs was differentially induced in response to methyl-jasmonate and ethylene treatment. In addition, ORCA6 activated the strictosidine synthase (STR) promoter in tobacco cells. Activation of the STR promoter was significantly higher when ORCA2 or ORCA6 was coexpressed with the mitogen-activated protein kinase kinase, CrMPKK1. Furthermore, transient overexpression of ORCA6 in C. roseus flower petals activated TIA pathway gene expression and TIA accumulation. The results described here advance our understanding of regulation of TIA pathway by the ORCA gene cluster and the evolution for plant ERF gene clusters.

Original languageEnglish
Article number110408
JournalPlant Science
Volume293
DOIs
StatePublished - Apr 2020

Bibliographical note

Publisher Copyright:
© 2020

Keywords

  • Catharanthus roseus (Madagascar periwinkle)
  • ORCAgene cluster
  • Terpenoid indole alkaloids (vinca alkaloids)
  • Transcriptional regulation

ASJC Scopus subject areas

  • Genetics
  • Agronomy and Crop Science
  • Plant Science

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